Effect of decreasing dietary protein levels with optimum amino acids profile on the performance of broilers

Pakistan Veterinary Journal 01/2004; 24.
Source: DOAJ

ABSTRACT A six-week trial was conducted to study the effect of decreasing dietary crude protein (CP) level on the performance of broilers in hot climatic conditions. Four experimental rations having CP 23 (control group), 22, 21 and 20%, with optimal amino acid balance were prepared. All the four rations were isocaloric having ME 3200 kcal/kg with Energy: Protein (E:P) 139.0, 146.5, 152.4 and 160 in diets A, B, C and D respectively. One hundred and twenty day-old chicks were randomly distributed into 12 experimental units, each having 10 chicks. Rations were randomly allotted to experimental units such that each unit received three replicates. The experimental diets were fed to birds from day 1st to 42nd. Performance of birds was monitored in terms of weight gain, feed consumption and feed conversion ratio (FCR). At the end of experiment, two birds per each replicate were randomly selected and slaughtered to record the data on carcass yield, breast meat yield, abdominal fat and composition of breast meat. Results of the trial suggested that weight gain was significantly (P<0.01) increased in birds on diets with CP 20 and 21%. Feed consumption and FCR remained un-changed for all the treatment groups. Eviscerated carcass yield was significantly (P<0.05) higher for the group fed on diet with 20% CP. Breast meat yield, abdominal fat and composition of breast meat also remained un-changed. Economic evaluation of the trial revealed that decreasing CP levels from 23 to 20% resulted in reduced feed cost per kg of live weight gain, which clearly indicated that this approach was useful especially in severe summer conditions. The overall picture of the study suggests that dietary protein level of broilers could be reduced from 23 to 20%, with beneficial effects on growth performance and carcass characteristics and increased economic returns in hot environmental conditions, provided that levels of essential amino acids are closely looked after.

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Available from: Zahid Kamran, Jan 26, 2014
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    • "Energy is offered for body function, and high energy diets result in extra deposition of fat pointing the wastage of dietary energy (Holsheimer and Jensen, 1991). Protein is an essential constituent of all tissues of body, and that having major effect on growth performance of the broilers is the most expensive nutrient in chicken diets (Kamran et al., 2004). However, the study of quality restriction synchronously including energy and protein has few been reported. "
    Italian Journal of Animal Science 05/2015; 14(2). DOI:10.4081/ijas.2015.3729 · 0.72 Impact Factor
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    • "It is common practice in the poultry industry to provide varying diets during the growing period. Protein is an essential constituent of all tissues of animal body and has major effect on growth performance of the bird [2]. A better understanding of the nutritional requirements of amino acids allows a more precise nutrition, offering the possibility for the formulator to optimize the requirement of at least minimum levels of crude protein by essential amino acids requirements, generating better result and lower costs for the producer [3]. "
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    ABSTRACT: Four experiments were conducted, in two stages, to evaluate protein and limiting amino acids' (lysine and methionine + cystine) levels in pre-starter diets on broilers' performance. In each experiment of Stage 1, 640 new-born male Ross 308 cockerels were randomly allocated to eight dietary treatments with a 2 × 4 factorial arrangement. In experiment 1-1, two levels of crude protein (CP: 21% and 23.2%) and four levels of Lys (1.2, 1.3, 1.4, and 1.5%) and in experiment 1-2, two levels of CP (21 and 23.2%) and four levels of Met + Cys (0.85, 0.90, 0.95, and 1.00%) were used. In Stage 2, the optimum levels of Lys and Met + Cys obtained from Stage 1 (1.3 and 1.5% Lys, 0.90 and 1.00% Met + Cys in experiment 1-1 and 1-2, resp.) with two levels of CP (21 and 23.2%) were used in two separate simultaneous experiments with a 2 × 2 factorial arrangement for male and female birds. The levels of CP significantly influenced BWG and FCR in experiment 1-1. Dietary levels of Lys affect BWG (experiment 1-1) and FI (experiments 1-1 and 2-1) significantly. In experiments 1-2 and 2-2, the different levels of Met + Cys did not affect BWG, FI, and FCR of male or female broilers. The results of these experiments indicated that the optimal level of dietary protein and Lys were 23.2% and 1.5%, respectively. Diets with 1% Met + Cys caused optimal performance.
    Veterinary Medicine International 09/2012; 2012:394189. DOI:10.1155/2012/394189
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    • "The feed to gain ratio was not influenced indicating that the light depression in BW gain of birds receiving the low CP diet was associated with reduced feed consumption rather than with problems of nutrient digestibility. These results agree in part with those reported by Kamran et al. (2004) and Azarnik et al. (2010) who observed no difference in feed consumption or FCR of broilers when dietary CP contents were decreased from 23 to 20% under hot climatic conditions. Conversely, our results disagreed with the findings of Kidd et al. (2001) who reported significant increase in feed intake when broilers were fed a diet with 20% CP and supplemented with amino acids, when compared with those fed a diet with 23% CP. "
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    ABSTRACT: This study examined the effect of different crude protein (CP) levels in the diet on growth performance of broilers as well as the total aerobic mesophilic count (TAMC) and Escherichia coli count (ECC) isolated from chicken faeces. A total 150 day-old broilers (Hubbard) were allocated to three treatments with five replicates containing 10 birds. The dietary treatments consisted of three diets with different CP levels for 42 days: high-protein (HCP, 22.5%), medium-protein (MCP, 20.5%), and low-protein (LCP, 18.5%). Body weight and feed intake were determined and the feed conversion ratio was calculated. Faecal samples were collected at 14, 21 and 42 days. Dietary CP did not affect the growth performance of broilers. Reducing CP level was effective at beneficially modulating the composition of the faecal microflora, in particular TAMC and ECC concentrations (log 10 CFU g –1) were significant lower for the LCP birds. During hot temperature conditions (33°C and 70% relative humidity) a low protein diet may help to control the characteristics of the faecal microbial community without negative effects on broiler performance.
    Avian biology research 06/2012; 5(2):88-92. DOI:10.3184/175815512X13350180713553 · 0.93 Impact Factor
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